After being evacuated due the discovery of a potentially dangerous substance a group of workers walk back to their jobs at the Mars Building on College St., Toronto.Fernando Morales/The Globe and Mail
The discovery of a small quantity of a potentially explosive chemical sent about 600 people to the sidewalk for an hour at Toronto's Mars Centre research facility.
Toronto fire and police officials ordered the evacuation of the entire centre, which comprises three buildings containing medical laboratories and offices, from about 10:30 to 11:30 a.m. on Tuesday.
The precaution was taken after a worker in a third-floor laboratory in the centre's Toronto Medical Discoveries Tower noticed a bottle containing a small amount of picric acid that had dried out. The substance, widely used in the staining of tissue for analysis, is stable in liquid form but explosive when dry.
"We think of it as a workplace hazard, and we are very, very cognizant of trying to make our workplace safe, but we don't think of it as a public safety hazard," said Dr. Christopher Paige, vice-president of research for the University Health Network, which runs the lab in question. "Evacuating a building sounds more like a public safety hazard," he said, but added, "better to be safe than sorry."
A Toronto fire department spokesman called the evacuation and removal of the chemical a "pretty routine operation" meant to ensure everyone's safety.
Dr. Paige said UHN's labs have rules in place to track the use of picric acid because it is a known hazard, and "where specific instructions, like 'don't let this stuff dry out', are necessary, then our internal regulatory group would go around and make sure that all of those labs know that."
The fact that a worker noticed a problem Monday shows that, in a sense, "that worked today, because somebody saw it and realized it was picric acid and that it shouldn't be dry." The worker then blocked off the area and notified security, "and then the rest rolled out as it should," Dr. Paige said.
UHN officials will revisit the incident and decide whether internal procedures need to be changed, he said.